Synthesis of new metal complex - Bioinolecule hybrids as redox sensors for specific nucleobases

This article describes the synthesis, characterization and Zn(II) complexation properties of a macrocyclic tetraamine ligand derivative of 1,4,7,10-tetraazacyclododecane (cyclen) (1) bearing a ferrocenyl pendant arm. Functionalization of cyclen with the ferrocenyl group has been accomplished according to a published method. NMR spectroscopy has been used to establish that the ligand forms a Zn²⁺ complex with a 1:1 stoichiometry. We have investigated the change in the redox properties of the metal-free ligand 1, the Zn²⁺ complex and the Zn²⁺ complex following addition of the DNA base thymine (T) in acetonitrile as solvent. The electrochemical data indicate a significant change in the redox potential of the ferrocenyl group on addition of zinc ions to the macrocycle-ferrocenyl adduct. Addition of thymine to the complex caused only a minor change in electrochemical response, which indicated that this Zn(II)-ferrocene hybrid is unlikely to useful as a thymine sensor under the conditions used in our experiments.